Model Comparison

GPT OSS 20B vs Kimi K2 Base

Both models are evenly matched across the benchmarks.

Want to compare interactively?Try the playground

Performance Benchmarks

Comparative analysis across standard metrics

2 benchmarks

GPT OSS 20B outperforms in 1 benchmarks (GPQA), while Kimi K2 Base is better at 1 benchmark (MMLU).

Both models are evenly matched across the benchmarks.

Tue May 26 2026 • llm-stats.com

Arena Performance

Human preference votes

Model Size

Parameter count comparison

979.1B diff

Kimi K2 Base has 979.1B more parameters than GPT OSS 20B, making it 4684.7% larger.

OpenAI
GPT OSS 20B
20.9Bparameters
Moonshot AI
Kimi K2 Base
1.0Tparameters
20.9B
GPT OSS 20B
1000.0B
Kimi K2 Base

Context Window

Maximum input and output token capacity

Only GPT OSS 20B specifies input context (131,072 tokens). Only GPT OSS 20B specifies output context (32,768 tokens).

OpenAI
GPT OSS 20B
Input131,072 tokens
Output32,768 tokens
Moonshot AI
Kimi K2 Base
Input- tokens
Output- tokens
Tue May 26 2026 • llm-stats.com

License

Usage and distribution terms

GPT OSS 20B is licensed under Apache 2.0, while Kimi K2 Base uses MIT.

License differences may affect how you can use these models in commercial or open-source projects.

GPT OSS 20B

Apache 2.0

Open weights

Kimi K2 Base

MIT

Open weights

Release Timeline

When each model was launched

GPT OSS 20B was released on 2025-08-05, while Kimi K2 Base was released on 2025-07-11.

GPT OSS 20B is 1 month newer than Kimi K2 Base.

GPT OSS 20B

Aug 5, 2025

9 months ago

3w newer
Kimi K2 Base

Jul 11, 2025

10 months ago

Knowledge Cutoff

When training data ends

Neither model specifies a knowledge cutoff date.

Unable to compare the recency of their training data.

No cutoff dates available

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Key Takeaways

OpenAI
Larger context window (131,072 tokens)
Higher GPQA score (71.5% vs 48.1%)
Moonshot AI
Higher MMLU score (87.8% vs 85.3%)

Detailed Comparison

AI Model Comparison Table
Feature
OpenAI
GPT OSS 20B
Moonshot AI
Kimi K2 Base

FAQ

Common questions about GPT OSS 20B vs Kimi K2 Base.

Which is better, GPT OSS 20B or Kimi K2 Base?

Both models are evenly matched across the benchmarks. GPT OSS 20B is made by OpenAI and Kimi K2 Base is made by Moonshot AI. The best choice depends on your use case — compare their benchmark scores, pricing, and capabilities above.

How does GPT OSS 20B compare to Kimi K2 Base in benchmarks?

GPT OSS 20B scores MMLU: 85.3%, CodeForces: 74.3%, GPQA: 71.5%, TAU-bench Retail: 54.8%, HealthBench: 42.5%. Kimi K2 Base scores C-Eval: 92.5%, GSM8k: 92.1%, MMLU-redux-2.0: 90.2%, MMLU: 87.8%, TriviaQA: 85.1%.

What are the context window sizes for GPT OSS 20B and Kimi K2 Base?

GPT OSS 20B supports 131K tokens and Kimi K2 Base supports an unknown number of tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between GPT OSS 20B and Kimi K2 Base?

Key differences include licensing (Apache 2.0 vs MIT). See the full comparison above for benchmark-by-benchmark results.

Who makes GPT OSS 20B and Kimi K2 Base?

GPT OSS 20B is developed by OpenAI and Kimi K2 Base is developed by Moonshot AI.